Apathetic thyrotoxicosis presenting with diabetes mellitus.

Apathetic form of thyrotoxicosis occurs in the elderly who can present with features of hyperglycemia, hypothyroidism, depression, or an internal malignancy. A clinical suspicion and timely diagnosis of hyperthyroidism is needed to define the correct etiology of existing problems, and to prevent grave complications. We discuss an 84-year-old woman who presented with fatigue and uncontrolled diabetes due to apathetic thyrotoxicosis.